Resource Efficiency in MANETs: Effect of Spurious Timeouts and Routing Protocol Dynamics

The presence of delay-sensitive traffic in QoS-aware MANETs (mobile ad-hoc networks) results into increased TCP spurious timeouts, thus wasting their scarce bandwidth. Furthermore, the different dynamics used by a routing protocol in discovering and maintaining routes have a significant impact on TCP and MANETs in general. In this paper, we investigate the combined effect of contention- induced spurious timeouts and the routing protocol dynamics on the resource efficiency of TCP in the presence of prioritised VoIP traffic. Through simulation study, TCP performance is contrasted against that of our proposed enhancement to limit spurious timeouts in QoS-aware MANETs (RE-TCP). Our simulations results show that although proactive protocols deliver TCP traffic with the smallest delay and retransmit fewer TCP segments, reactive protocols are able to achieve better throughput and reduce TCP starvation in presence of high priority VoIP traffic. It has also been shown that RE-TCP is able to achieve a 10% gain in bandwidth utilization.